We will continue studies of four distinct hemolytic anemias, including analysis of membrane defects and search for methods for early identification of heterozygous carriers. We will continue studies of macrocytic anemias, with special attention to pleiotropic effects associated with Hertwig's anemia. We will compare hematology and pleiotropic effects of 10 previously unstudied putative W alleles. We will pursue genetic, developmental and biochemical studies of mouse hemoglobins, including regulation of proportion of minor hemoglobins during development and analysis of a thalassemia-like mutant.